Lift a migration from Pro -- workspace_members

Should have landed here initially anyway.

data/sql/migrate/20120411173220_rename_workspace_members.rb

@@ -0,0 +1,9 @@
+class RenameWorkspaceMembers < ActiveRecord::Migration
+  def up
+    rename_table :project_members, :workspace_members
+  end
+
+  def down
+    rename_table :workspace_members, :project_members
+  end
+end